Five patients with concentric left ventricular hypertrophy, non-dilated hearts and left ventricular outflow tract obstruction (with systolic anterior motion of the anterior mitral leaflet, i.e., SAM on echocardiogram) were identified. Two of these patients had documented evidence of typical hypertrophic cardiomyopathy in their relatives. Hence, left ventricular outlfow obstruction may occur in the presence of asymmetric septal hypertrophy.